Towards new green polymers: terpene-derived monomers obtained in flow regime.

Significance 

The current global focus is delivering a more sustainable future. This includes imposing strict mitigation measures on the use of fossil fuels and increasing research investments on development and deployment of alternative renewable energy sources. Even though the use of fossil fuels cannot be currently eliminated considering that it is the largest global source of energy, the recent estimation that the oil, gas and coal reserves may be depleted in the next few centuries has resulted in a crisis in the sector, especially the fate of the future generation. To this end, development and expanding the use of alternative energy sources is highly desirable.

Biomass has been identified as a promising organic carbon source for the production of fuels, polymers and other related materials. This has led to the development of numerous chemical transformation strategies for development of bio-derived building blocks and monomers such as terpene-based polymers. Generally, these polymers are increasingly gained research interest due to their relatively low cost and natural availability in trees, flowers, and fruits. Consequently, these molecules exhibit different structural compositions that require different methods for conversion of terpene-based monomeric units into polymeric materials. Alternatively, several reactions such as Diels-Alder reaction have been developed to enable effective conversion of terpene starting materials into monomeric units. Unfortunately, most of these processes emphasize the specific terpene-derived monomers and polymers.

To this note, Brazilian scientists: Dr. Renan Galaverna, Lucas Fernandes and Dr. Julio Pastre from the University of Campinas together with Dr. Duncan Browne at Cardiff University in Wales developed a continuous flow processing method for the synthesis of monomers for the synthesis of green polymers. In particular, the continuous processing technique was used to synthesize two terpene-derived monomer libraries. The work is currently published in the research journal, Reaction Chemistry and Engineering.

Briefly, research team started their work by developing the continuous flow process for the preparation of the monomer libraries derived from renewable terpene feedstocks. Next, the library base comprised of small terpene range such as ocimene and myrcene. The first library was derived from a Diels-Alder reaction while the second library was derived from exhaustive hydrogenation of alkenes present in the first library by the help of tube-in-tube reactor (AF-2400) and Pd/C catalyst. Eventually, a Diels-Alder process was used to evaluate the scaling of the two libraries.

The use of continuous flow processing was more advantageous as compared to the conventional batch procedure. For instance, it offered large scale processing due to precise control of the reaction parameters and other factors such as higher surface area and improved heat and mass transfer. Additionally, they confirmed the scale-up potential for both libraries using Diels-Alder reaction and hydrogenation process. The former delivered 10.5 grams after 3 hours while the later delivered 10.5 grams after 16 hours.

In summary, the research team successfully developed and demonstrated the use of a continuous flow process for generating terpene-derived monomer libraries. It is worth noting the described process is capable of delivering multiple grams of monomer units without the use of loading loops. Considering the high productivity of the continuous flow process, the study by Dr. Julio Pastre and his colleagues will pave way for the synthesis of polymers derived from monomers with bicyclic rings for enhanced mechanical properties.

About the author

Dr Duncan Browne

Cardiff University
Senior Lecturer in Organic Synthesis and Medicinal Chemistry
School of Chemistry
Tel. : +44 (0)29 2087 5571,  e-mail : [email protected]

Duncan is a Senior Lecturer in the School of Chemistry at Cardiff University, his research is focused in the areas of synthetic organic chemistry, continuous flow processing and enabling chemical technologies. He is the lead of the Emerging Reactor Technologies sub-theme of the EPSRC’s Dial-a-Molecule Grand Challenge Network. In 2017 he was recognised as an ‘Emerging Investigator’ by Reaction Chemistry and Engineering and Green Chemistry and was the recipient of a 2017 Thieme Chemistry Journal Award. Duncan was an Undergraduate at University of Sheffield (2002-2006), PhD at University of Sheffield with Prof Joe Harrity (2006-2009), an EPSRC Doctoral Prize Fellow (2009-2010) and a Postdoc at Cambridge University with Prof Steve V. Ley FRS CBE (2010-2014). Appointed to Lecturer in Cardiff in 2014 and promoted to Senior Lecturer in 2018.

About the author

Julio C. Pastre was born in Brazil in 1979. He obtained his PhD in 2009 under the guidance of Professor Carlos Roque D. Correia at the University of Campinas – UNICAMP. This was followed by a brief one-year spell working as a process chemist at Rhodia. He then spent three years as a postdoctoral researcher at UNICAMP with Professor Ronaldo A. Pilli and joined the group of Professor Steven V. Ley at the University of Cambridge as a Postdoctoral Research Associate.

Since 2014, he is working as an Assistant Professor at UNICAMP, and his general areas of interest focuses on the development of new synthetic methods in batch and continuous flow regime for the synthesis of natural products, new materials, drugs and biomass conversion.

About the author

Lucas Pera Fernandes was born in São Paulo, Brazil in 1995. He is an undergraduate student in a bachelor’s degree in technological chemistry from the Chemistry Institute of University of Campinas – UNICAMP. He began his undergraduate research under the guidance of Professor Julio Cezar Pastre in 2017 as scientific initiation student. Since then, he has been developing research in the field of organic chemistry with emphasis on the development of new synthetic methods in batch and continuous-flow regimes for the generation of renewable bio-based building blocks and new materials.

He is currently starting an internship program at Rhodia company of the Solvay group.

About the author

Renan S. Galaverna was born in Brazil in 1989. He obtained his PhD in 2019 under the guidance of Prof. Julio C. Pastre at the University of Campinas – UNICAMP. This was followed by a brief one-year spell as visiting student at Cardiff University under supervision of Prof. Duncan L. Browne.

His main current research interests include the development in the area of flow chemistry technologies for the development of new methodologies in organic synthesis, synthesis of biomass-based compounds and medicinal chemistry, working on new strategies for organic drug synthesis.

Reference

Galaverna, R., Fernandes, L., Browne, D., & Pastre, J. (2019). Continuous flow processing as a tool for the generation of terpene-derived monomer libraries. Reaction Chemistry & Engineering, 4(2), 362-367.

Go To Reaction Chemistry & Engineering

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